Filter



FIG. 1 is a top perspective view, showing my new design for a filter;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right-side elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines show portions of the filter that form no part of the claimed design. 

CLAIM I claim the ornamental design for a filter, as shown and described. 